Air signalling drift apparatus with blow tube

ABSTRACT

An air signalling drift apparatus in which a knob tube is axially shiftable in one direction in a pulse tube when air well drilling fluid circulation is arrested to uncover a number of ports representative of the angle of drift of the drill stem from vertical, through which ports air sequentially passes upon resumption of circulation and the knob tube moves axially in the other direction, to create pressure pulses in the fluid stream detectable at the top of the well and indicative of the angle of drift, and wherein a blowtube is provided to shield the upper end of the knob tube from the accumulation of foreign matter.

Unite States atent Inventors Wayne M. Sullivan;

John W. Turner, ,lr.. both of Houston, Tex. App]. No, 756,083 Filed Aug.12, 1968 Patented June 29, 1971 Avignon Byron Jackson lnc.. LongBeach,Calif.

('nntinuatiun-in-part ofh'er. Nu. S8l.-l76. Sept. 23. I966. abandoned.

AIR SIGNALLING DRIFT APPARATUS WITH BLOW TUBE 17 Claims, 6 Drawing Figs.

US. Cl 33/205, 175/45 Int. Cl G01c 9/00 Field of Search .t 33/205,

205.5,2055 E; l75/45;73/l52, 155; 166/250 1 a ma [56] References CitedUNITED STATES PATENTS 3,303,573 2/1967 Alder etal. 33/205 PrimaryExaminer-Leonard Forman.

Assistant Examiner-Steven L. Stephan Attorneys-Donald W. Banner, Lyle S.Motley, C, G Stallings and William S. McCurry ABSTRACT: An airsignalling drift apparatus in which a knob tube is axially shiftable inone direction in a pulse tube when air well drilling fluid circulationis arrested to uncover a number of ports representative of the angle ofdrift of the drill stem from vertical, through which ports airsequentially passes upon resumption of circulation and the knob tubemoves axially in the other direction, to create pressure pulses in thefluid stream detectable at the top of the well and indicative of theangle of drift, and wherein a blowtube is provided to shield the upperend of the knob tube from the accumulation of foreign matter.

PATENTEU JUN29 um SHEET 3 OF 3 AIR SIGNAILLING DRIFT APPARATUS WllTlHlBLOW TUBE CROSS-REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of U.S. application, Ser. No. 581,476, filed Sept.23, 1966 for an AIR SIGNALLING DRIFT APPARATUS, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention In the drilling ofwells, such as oil and/or gas wells, it sometimes is necessary todetermine at intervals the angle of deviation of the well from verticalas the drilling progresses, either for the purpose of maintaining thewell as nearly as possible on a vertical axis, or to effect the desiredangular deviation ofthe well. Thus, the need arises for signalling driftindicator apparatus capable of periodic operation without undueinterruption in the drilling progress.

Signalling drift indicators of the general type here involved are shownin patents heretofore issued to F. M. Varney et al., U.S. Letters Pat.No. 2,435,934, Feb. 10,1948; J. A. Varney, U.S. Letters Pat. No.2,762,132, Sept. Ill, 1956; and R. L. Alder et al., U.S. Letters Pat.No. 3,176,407, Apr. 6, 1965, as well as in the application for U.S.Letters Pat. filed July 1, 1966, Ser. No. 562,146, in the name of R. LvAlder, now U.S. Letters Pat. No. 3,457,654, July 29, 1969. As will berecog nized from these prior inventions, pressure pulses or signals maybe produced in the stream of drilling fluid adjacent the drill bit anddetected or recorded at the earths surface as an indication of the angleof the lower end of the drill string from vertical, such signals beinggenerated in a number which is either directly or inversely related tothe angularity of the drill string adjacent the bit. Such devices are ofsubstantial benefit to the proper control of the weight to be applied tothe drill bit in order to maintain the desired control over the verticalprogression of the drilling operation, as well as being of sub stantialbenefit to the driller in determining relative bit effciency, i.e.,whether the bit should be changed to enable increased penetration rateat a given depth in the light of the time required to make a round tripof the drill pipe to change bits, all as is now well known in the art.

Heretofore, in the use of devices of the general type discussed above,it has been the practice to cause operation of the signal-producingmeans in response to the cessation and resumption of the circulation ofdrilling fluid. In such devices, cessation of drilling fluid circulationallows for upward travel of a flow pressure responsive head or knobthrough a series of restrictions, and resumption of drilling fluidcirculation causes downward travel of the knob through a number of therestrictions related to the angle of the drill string, or more preciselythe drill collar sub, in which the knob is disposed. Means are includedin such devices which are operative in response to gravity to limitupward travel of the knob in a particular rela tion, which limitation oftravel is directly or inversely related to the angle of the sub.However, when air or gas, hereinafter referred to simply as air, isemployed as the drilling fluid, the typical pressure pulse producingmeans which produces clear discriminate signals in a liquid column hasbeen found to be wanting due primarily to the compressibility of theair. When liquid is employed, large clearances between the conventionalpulse rings and the traveling knob may be tolerated, but when air isemployed the clearances which will permit loss of air should beminimized or controlled to the end that an adequate pressure reductionoccurs at spaced intervals as the knob is moved downwardly andalternately pressure builds up sufficiently to produce pressure signalswhich are clearly distinguishable at the earths surface upon referenceto a pressure guage or recorder.

SUMMARY The present invention relates to signalling drift indicators foruse in the drilling of boreholes or wells through or into the earth, andmore particularly to improvements in the signalproducing means of theinstrument whereby it is better adapted to use when gas or air isemployed as the drilling fluid.

The present invention provides pressure pulse or signalproducing meansfor signalling drift indicators particularly adapted for use in drillingoperations in which air is employed as the drilling fluid. Inaccomplishing this, there is provided a pulse tube providing a flowpassage through the instrument and having in alternate axially spacedrelation a number of ported and unported sections, and cooperative withthe pulse tube is a head or knob having an axially extended tubecoaxially arranged with the pulse tube, this knob tube having a portarrangement so related to the ported and unported sections or the pulsetube that the ported sections of the latter will be sequentially openedto allow bypass of air around the knob as the knob tube moves axially ofthe pulse tube, thus producing sequential pressure reductions and risesin the flowing airstream.

More particularly, the invention provides in combination with gravityresponsive control means, air pressure pulseproducing means including aknob tube normally biased upwardly within a pulse tube but being forceddownward responsive to the circulation of air downward through thetubes, the gravity responsive means being operable to limit upwardtravel of the knob tube to an extent representative ofthe angulardisposition of the drill collar sub in which the instrument is disposedwhen air circulation is interrupted, and the pulse tube and knob tubehaving valve means for causing successive pressure cycles or pulses asthe knob trube moves downward upon resumption of circulation of the air,the valve means comprising alternate ported and unported sections in oneof the tubes and at least one port in the other tube adapted forprogressive communication with said ported sections as the knob tube ismoved downward, such cycles or pulses resulting in signals which aredetectable at the earth s surface as an indication of the angulardisposition of the instrument relative to vertical.

A pulse tube and knob tube construction is provided in accordance withthe foregoing, wherein the tubes are ported in such a fashion that thesame flow area is provided when the ports are aligned or opennotwithstanding relative rotation between tee tubes, thus allowingfreedom or rotation of the tubes one within the other and eliminatingthe use of key or other means to assure proper port alignment.

In one embodiment of the invention there is provided a blow tube whichshields the structure from the accumulation of adverse deposits of suchmatter as water, grease from tool joint connections, dirt from the drillpipe, bits of wood splinters, sulfur from gas, or the like which havebeen found to cause deposits varying from gummy consistency to firmflaky material. More particularly, the blow tube is disposed in the knobtube and provides a shield means for preventing the accumulation of suchdeposits above the shoulder inherently provided at the upper end of theknob tube, either on such shoulder or on the interior cylindrical wallof the pulse tube.

Accordingly, an object of the invention is to provide pressure pulse orsignal-producing means for signalling drift indicators particularlyadapted for use in drilling operations in which air is employed as thedrilling fluid. In accomplishing this objective there is provided apulse tube providing a flow passage through the instrument and having inalternate axially spaced relation a number of ported and unportedsections, and cooperative with the pulse tube is a head or knob havingan axially extended tube coaxially arranged with the pulse tube, thisknob tube having a port arrangement so related to the ported andunported sections of the pulse that the ported sections of the latterwill be sequentially opened to allow bypass of air around the knob asthe knob tube moves axially of the pulse tube, thus producing sequentialpressure reductions and rises in the flowing airstream, but the pulsetube and knob tube being shielded by a blow tube to prevent accumulationof deposits at the upper end of the knob tube.

Other objects and advantages of the invention will be hereinafterdescribed or will become apparent to those skilled in the art, and thenovel features of the invention will be defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a drillcollar sub broken away to expose in longitudinal section an instrumentmade in accordance with the invention with the knob tube depressed bythe downward flow of air through the instrument;

FIG. 2 is a fragmentary view in longitudinal section, showing thepulse-producing means of the invention in one position of limited upwardmovement of the knob tube upon interrup tion of the downward flow of airthrough the instrument;

FIG. 3 is a fragmentary view showing the pulse tube and knob tube ofFIG. 2 with ports open in response to resumption of the downward flow ofair through the instrument and downward movement of the knob tube;

FIG. 4 is an enlarged transverse sectional view as taken on the line4-of FIG. 3;

FIG. Sis a view generally corresponding to FIG. 2 but showing a modifiedembodiment of the invention; and

FIG. 6 is a fragmentary view showing the pulse tube and knob tube ofFIG. 5 with the ports closed in response to re sumption of the downwardflow of air through the instrument and downward movement of the knobtube.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1,there is shown an instrument made in accordance with the invention anddisposed in a drill collar sub C, having a body 1, pin end 2, and a boxend 3 for threaded connection in the drill string. Pin end 2 is formedon a cap 4 which is suitably removably connected to the body 1 as by athread (not shown) whereby the instrument may be in stalled in thebody 1. This instrument includes a pulse or signal producing section Pand a shaft and pendulum section S. The latter section 5 includes ahousing 5 and at the lower end of which is a bottom support 6 in theform of a spider providing flow passages 7, this bottom support seatingon a shoulder 8 at the bottom of drill collar body 1. Housing 5 ofsection S is connected by a spider 9 having flow passages R0 to a pulsesection P, and the pulse section P includes a housing ll which extendsupwardly in the drill collar body 1 and is provided with an upper flange12. Above flange 12 is a pair of resilient packing rings 13 engaged bythe lower end of a spacer sleeve 14 extending upwardly for engagementwith the cap 4, whereby the entire instrument assembly is adapted to beheld in place in collar body 1 and seated on shoulder 8 at the bottomsupport 6.

The pulse-producing section P includes a stationary member or pulse tube15 welded as at 16 to the flange 12 of the housing 11 or otherwiseintegral with the housing 11. At its upper end the pulse tube 15 isprovided with debris catcher means in the form ofa ring 17 retained intube 15 by snaprings l8 and having a number of crossed pins 19 or otherobstructions to the downward passage of debris. In spaced relationaxially of the pulse tube 15 are alternate ported sections having ports20 and unported sections 21. The ports 20 lead from the central flowpassage through the pulse tube 15 into the annular space 22 formedbetween the pulse tube 15 and the housing 11.

Reciprocably disposed within the pulse tube 15 is a movable member orknob tube 23 of such a length as to extend upward in the pulse tube 15to a location above the uppermost of the ports 20 when the inner knobtube 23 is in the lowermost posi' tion, as shown in FIG. 1, thus closingall of the ports 20. In the inner knob tube 23 and below the lowerextremity of the pulse tube 15, when the inner knob tube 23 is in saidlowermost position of FIG. 1, is a number of knob tube ports 24,including in the illustrative embodiment a pair of axially spaced setsof ports 24, these sets of ports 24 being axially spaced a distancecorresponding to the axial distance between pulse tube ports 20 toenable alignment of ports 20 and 24 when the inner knob tube 23 is movedupwardly into the pulse tube 15. At its lower end, the knob tube 23 isconnected to a knob 25. Suitable sealing means 26 are provided betweenthe knob tube 23 and knob 25 and a snapring 27 or other suitable meansare employed for connecting the knob tube 23 to the knob 25.

It is notable that with the knob 25 in the position shown in FIG. ll.i.e., in its lowermost position, the ports 24 in knob tube 23 provide apath for the flow of air downward through the pulse tube 15 and knobtube 23 and out into the annular space 22 previously referred to.Thence, such air may flow downward through spider openings 10, along theoutside of the shaft and pendulum section S of the instrument, andopenings 7 in bottom support 6. Such flow of air will hold the knob 25and the knob tube 23 in the depressed position of FIG. 1.

Shaft and pendulum section S includes within its housing 5 a shaft 30which extends through the upper end of housing 5 and is connected to theknob 25. Within the housing 5 is a mainspring 31 which provides a forcenormally tending to push the shaft upwardly. Means are provided withinthe housing 5 for limiting upward movement of shaft 30 a distancerelated to the angle of drift of the drill collar sub C and the wellfrom vertical so that upward movement of knob 25 will be correspondinglylimited. As seen in FIG. 1, this means comprises a pendulum 32 pivotallysupported beneath shaft 30 by bail means 33 and having a head 34providing a shoulder which is selectively engageable with one of aplurality of axially spaced annular stops 35 of progressivelydiminishing diameter. It will be recognized that the angular dispositionof the drill collar sub C relative to the pendulum 32, which, beinggravity responsive will depend vertically from its pivot, will determinewhich stop 35 will be engaged by pendulum head 34, and that while in thestructure shown the permitted upward travel of the pendulum and theshaft is inversely related to the angular disposition of the body I,i.e., the greater the angle the less the travel, the assembly mayinclude a coding system for enabling a direct relationship between angleand extent of shaft travel, as disclosed in the aforesaid U.S. LettersPat. No. 3,176,407.

In either event, downward movement of the knob 25 and connected knobtube 23 responsive to flow of drilling fluid or air through certainports 24 and 20 will cause the production of a pressure signal in thestream of air which is detectable at the earths surface for purposes ofindicating the angle of the drill collar sub C. In order that the pulseswill be of sufficient duration so as to be easily discriminated fromnormal pressure variations in the fluid stream, a clean body of oil inthe shaft and pendulum section S is displaced through an orificeassembly including a number of orifice discs 36 which are disposed in apassage 37 in a combined disc support and pendulum seat 39 which ismounted in the housing 5 between rings 40. A bypass passage 41 and adownwardly closing check valve 42 are provided in the support 39 forallowing relative freedom of upward movement of instrument fluid inhousing 5 through support 3Q during upward movement of shaft 35).

This clean oil or instrument fluid is retained in the housing 5 by meansof a seal ring 43 which is interposed between the upper end of housing 5and the shaft 30 and by a pressure equalizing divider below the support39. The divider in the illustrative embodiment is in the form ofadiaphragm 44, but a free piston may also be employed.

Referring now to FIGS. 2 through 4, the details of the illus trativeembodiment of the pulse or signal-producing section P of the inventionwill now be described with greater particularity as regards the valveaction of the tubes 15 and 23.

In fig. 2 the knob 25 and knob tube 23 have moved upward from theposition shown in FIG. I, as would occur upon interruption of thedownward flow of air through the drill string,

ward movement of the knob is limited by the pendulum 32 which engagesone of the stops 35 and thereby determines the limit of upward travel ofshaft 30 as a function of the angular disposition of drill collar sub Crelative to vertical. The knob tube ports 24 and pulse tube ports 20 arespaced in this embodiment such that when pendulum head 34 is engagedwith any one of the annular stops 35 the knob tube ports 24 are oppositeunported sections 21 of the pulse tube 15. Thus, when airflow into thedrill string is resumed, a minimum of air will bypass thepulse-producing means as pressure is developed therein. When thepressure reaches a level at which a force is produced acting downwardlyon the knob 25 and knob tube 23 to overcome the upwardly acting force ofmainspring 31, the knob and knob tube will move downward to the positionshown in FIGS. 3 and 4, at which position knob tube ports 24 are inregistry with one set of pulse tube ports 20, at which time the airpressure will drop as air flows through the registered ports, as shownby the arrows in FIG. 4. Then, the knob and knob tube will continue tomove downward due to pressure acting on the knob until the knob tubeports are op posite a lower unported section 21 of the pulse tube 15,thereby causing an increase in pressure and completing a full pressurecycle which is reflected in the body of air in the drill string as adetectable and recordable pressure pulse. Obviously, the number ofpulses thus produced will be indicative of the number of unportedsections 21 of the pulse tube traversed by the ports 24 of the knob tube23, as the latter moves downward, the extent of such travel dependingupon the extent of initial upward travel of the knob 25 under thelimiting control of the gravity responsive pendulum.

It will be appreciated from the foregoing that the flow area through theports 20 and 24 when they are in registry should be large enough toallow a substantial drop in pressure as compared with the pressure whenthe knob ports 24 are opposite unported pulse tube sections 21, so thata discrete pressure signal will be produced, but yet it is necessarythat this flow area be sufficiently restricted as to not bleed off airto such an extent as to negate the continued downward movement of theknob 25 and knob tube 23 against the counterforce of mainspring 31.Since the airflow conditions may vary in different drilling operations,it is apparent that the detachable connection of the knob tube 23 to theknob tube 25 enables substitution of knob tube 23 with various portarrangements as may be found necessary or desirable in relation to agiven pulse tube port arrangement. However, the arrangement shown indetail in FIGS. 2 through 4 has been found to be quite satisfactory interms of reliable production of discrete pressure signals at the earthssurface. In this connection, it is notable that the pulse tube ports 20and the knob tube ports 24 are respectively in the form of elongatedslots extended circumferentially of the respective tubes and interruptedby tube sections a and 2311 (FIG. 4) spaced 120 apart, the ports havinga greater angular extent than sections 23a, and the ports 24 having agreater angular extent than the sections 1511. Therefore, as indicatedabove, the relative orientation of the tubes 15 and 23 about theircommon longitudinal axis is immaterial to the net flow area through theports when they are in registry.

Referring to FIGS. 5 and 6, a modified construction is illustrated.

As seen in these FIGS. of the drawings, it will be noted that the upperextremity 23b of the knob tube 23 provides a ledge or shoulder slidablewithin the cylindrical bore of the pulse tube 15 which, if exposed tothe flow of air downwardly therethrough, would be subject to theaccumulation of deposits thereon of any foreign matter entrained in theair, such as mud, dirt, grease from the drill pipe tool joints, woodsplinters, sulfur from gas, or the like. Ifdrilling progresses for aprolonged period without lIltCl'lL lllOl'l such deposits may besubstantial if allowed. However, in accordance with the presentinvention no such accumulation of deposits can occur. To avoid thisproblem the invention provides a tubular member 17a, which may becharacterized as a blow tube. This blow tube 170, as seen in FIG. 5, hasits lower extremity ex tending into the upper end of the knob tube 23,when the knob tube is in its lowermost position, The blow tube 17aprovides shielding means for the shoulder or ledge 23b on the knob tube23 protecting tee ledge 23b and the bore of the pulse tube I5 from theflow of air.

Suitable means are provided for supporting the blow tube in position,and, in the illustrative embodiment, the tube is formed as an integralcylindrical downward extension of the debris catcher ring l7. Since theinside diameter of the blow tube I7a is less than the inside diameter ofthe knob tube 23, and is elongated so as to form a nozzle the velocityof air traveling through the assembly is increased, thus tending toreduce the likelihood of deposits, as aforesaid, forming in the knobtube ports 24.

Thus, the blowtube 17a has the dual function of forming means forshielding the end 23 of the knob tube and the bore of the pulse tube 15from the airstream as well as providing nozzle means for increasing thevelocity of airflow in advance of flow through the knob tube ports 24.

In the embodiment of the invention as shown in FIGS. 1 through 4, aspreviously described, the ports 24 in the knob tube 23 and the ports 20in the pulse tube 15 are so relatively axially spaced that when theupward movement of the shaft 30 is arrested responsive to engagement ofthe head 34 of the pendulum 32 with one of the stop shoulders 35, theports 24 will be located between the ports 20, as seen in FIG. 2. In themodified construction as shown in FIGS. 5 and 6, the relative axialspacing of the ports 24 and 20 in the knob tube 23 and the pulse tube15, respectively, and the limit of upward travel of the knob tube 23 arearranged so that the knob tube ports 24 are aligned or in communicationwith the pulse tube ports 20 when the head 34 of the pendulum .32engages one of the stop shoulders 35, as is illustrated in FIG. 5. Thismodified arrangement of the ports 24 and 20 is such that the initialpressure cycle will be of greater magnitude: and more readily detectableat the top of the well than is the case with the first describedembodiment in which the ports 24 and 20 are out of registry when upwardmovement of the knob tube 23 is arrested. In this connection it will beunderstood that when the drilling fluid is a compressible fluid, such asair, the flow of air through the communicating ports 20 and 24, as shownin FIG. 5, will cause a gradual in crease in the air pressure in thedrill string above the instrument due to the pressure loss through theports 20 and 24. Therefore, the pressure acting to move the knob tube 23downwardly builds up gradually until such pressure is of sufficientmagnitude as to effect downward movement of the knob tube causingclosure of the ports 20, resulting in an immediate substantial increasein pressure which is rapidly bled off when the ports 24 and 20 are nextregistered. Thus there is produced an initial pressure pulse of greatermagnitude than will be produced when the ports 24 and 20 are in thestarting relationship shown in FIG. 2.

While the specific details of the invention have been herein shown anddescribed, changes and alterations may be resorted to without departingfrom the spirit of the invention.

We claim:

I. In signalling drift apparatus comprising: an elongated tubular bodyadapted to be installed in a well-drilling string and having apassageway therethrough for the flow of drilling fluid, pulse-producingmeans in said passageway including a movable member exposed to the flowof drilling fluid and held in a first position responsive to said flow,means for effecting movement of said movable member from said firstposition to another position related to the angular disposition of saidbody upon interruption of the flow of drilling fluid, and a stationarymember for effecting a number of pulses in said drilling fluid as saidmovable member returns to said first position upon resumption of saidflow; the improvement wherein one of said members is provided with aseries of opens therethrough and the other of said members is providedwith at least one opening therethrough, said at least one opening beingprogressively cooperative with said series of openings to allow thepassage of drilling fluid through said passageway when said at least oneopening is aligned with one of said series of openings, and to preventthe passage of drilling fluid when said at least one opening is notaligned with one of said series of openings.

2. Signalling drift apparatus as defined in claim 1, wherein saidmembers respectively are in the form of a pair of tubes, one tube beingcoaxially disposed with the other.

3. Signalling drift apparatus as defined in claim 2, wherein theopenings of each of said tubes are formed by circumferentially extendedslots, said tubes having unslotted sections intermediate the ends of theslots, said slots being longer than said unslotted sections.

4. Signalling drift apparatus as defined in claim 1, wherein the meansfor effecting movement of said movable member from said first positionincludes a spring and gravity responsive stop means for limiting saidmovement of said movable member to an extent related to the angulardisposition of said body.

5. Signalling drift apparatus as defined in claim 1, wherein said meansfor effecting movement of said movable member from said first positionincludes a shaft, said movable member being connected to said shaft, aspring acting on said shaft and normally biasing the same to move saidmovable member, gravity responsive stop means for limiting the extent ofsaid movement of said movable member from said first position, saidmovable member including a tube extending longitudinally in saidpassageway and said stationary member also including a tube extendinglongitudinally in said passageway in coaxial relation with said movabletube, at least one opening said tubes and said series of being in saidtubes.

6. Signalling drift apparatus as defined in claim 1, wherein saidmovable member comprises a longitudinally extended tube having said atleast one opening therein, said stationary member comprising a tubecoaxial with said movable tube and having said series of openings spacedaxially therealong.

7. Signalling drift apparatus as defined in claim 6, wherein saidmovable tube has a section without openings that extends along saidstationary tube and has an axial length greater than the total axiallength of the series of openings sections of said stationary tube forclosing the openings of all of said series of openings of saidstationary tube when said movable tube is in said first position.

8. Signalling drift apparatus as defined in claim 1, including means forshielding said tubes from the deposit of foreign matter thereon.

9. Signalling drift apparatus as defined in claim 8, wherein said meansfor shielding also provides nozzle means for increasing the velocity ofair flow through said movable member.

10. Signalling drift apparatus as defined in claim I, wherein saidmembers respectively are in the form of tube members, one tube memberbeing coaxially disposed within the other tube member, and includingmeans for shielding said tubes from the deposite of foreign matterthereon comprising a blowtube extending coaxially into the inner of saidtube members.

ll. Signalling drift apparatus as defined in claim 1, wherein saidmembers respectively are in the form of tube members, one tube memberbeing coaxially disposed within the other tube member, said series ofopenings and said at least one opening being provided in said tubemembers and being in the form of circumferentially extended axiallyspaced slots, and including means for shielding said tubes from thedeposit of foreign matter thereon comprising a blowtube extendingcoaxially into the inner of said tube members to a point spaced from thenearest slot.

12. Signalling drift apparatus as defined in claim 1, wherein said meansfor effecting movement of said movable member from said first positionincludes a shaft, said movable member being connected to said shaft, aspring acting on said shaft and normally biasing the same to move saidmovable member, gravity responsive stop means for limiting the extent ofsaid movement of said movable member from said first position, saidmovable member including a tube extending longitudinally in saidpassageway and said stationary member also including a tube extendinglongitudinally in said passageway in coaxial relation with said movablemember, said series of openings being in said tubes, and including meansfor shielding said tubes from the deposit of foreign matter thereoncomprising another tube extending axially into said tube of said movablemember.

13. Signalling drift apparatus adapted to be disposed in an elongateddrill collar sub, comprising: an elongated housing having a body ofclean fluid therein, a divider movably disposed in one end of saidhousing, a shaft reciprocable in said housing and having an endprojecting from the other end of said housing, means for effecting aseal between said shaft and said housing, a spring in said housingacting on said shaft for causing said shaft to be moved outward withrespect to said housing, gravity responsive stop means in said housingfor limiting outward movement of said shaft to an extent related to thedisposition of said housing relative to vertical, pulse tube meanscarried by said housing, a knob on said end of said shaft, knob tubemeans on said knob and extending axially into said pulse tube means,said pulse tube means and said knob tube means together operativelydefining valve means progressively openablc and closable in response tomovement of said knob tube means axially in said pulse tube means, ablowtube, means supporting said blowtube in coaxial relation to saidpulse tube means and said knob tube means with the lower end of saidblowtube telescopically fitting within said knob tube means.

14. In signalling drift apparatus comprising: an elongated tubular bodyadapted to be installed in a well drilling string and having apassageway therethrough for the flow of drilling fluid, pulse-producingmeans in said passageway including a movable member exposed to the flowof drilling fluid and held in a first position responsive to said flow,means for effecting movement of said member from said first position toanother position related to the angular disposition of said body uponinterruption of the flow of drilling fluid, and a stationary member foreffecting a number of pulse in said drilling fluid as said movablemember returns to said first position upon resumption of said flow; theimprovement wherein said stationary member comprises an elongated tubein said passageway, and said movable member comprises an elongated tubecoaxial with said stationary tube, one of said tubes having alternatelyin axially spaced relation therealong a series of openings connectingsaid passageway in said stationary tube with the passageway below saidstationary tube, said movable tube having at least one opening movablesuccessively past said series of openings of said stationary tube.

15. Signalling drift apparatus as defined in claim 114, wherein saidmovable tube includes a pair of axially spaced openings spaced adistance equal to the spaces between adjacent openings of said series ofopenings of said stationary tube for registry with the adjacent openingsof the latter.

l6. Signalling drift apparatus as defined in claim 15, wherein saidopenings of each of said tubes are formed by circumferentially extendedand circumferentially spaced said slots being longer circumferentiallythan the spacers therebetween.

l7. Signalling drift apparatus adapted to be disposed in an elongateddrill collar sub, comprising: an elongated housing having a body ofclean fluid therein, a divider movably disposed in one end of saidhousing, a shaft reciprocable in said housing and having an endprojecting from the other end of said housing, means for effecting aseal between said shaft and said housing, a spring in said housingacting on said shaft for causing said shaft to be moved outward withrespect to said housing, gravity responsive stop means in said housingfor limiting outward movement of said shaft to an extent related to thedisposition of said housing relative to vertical, pulse tube meanscarried by said other end of said housing and extending axiallytherefrom, a knob on said end of said shaft, knob tube means on saidknob and extending axially into said pulse tube means, said knob tubemeans and said pulse tube opening in the other of said tube means, andsaid other tube means having a section without openings for closing allof said series of openings of said one of said tube means upon inwardmovement of said shaft to its innermost position.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,59: Dated June 99: 97

fl Wayne M. Sullivan and John W. Turner, Jr.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Col. 2, line 17, "or" should be --of----;

line M7, "tee" should be --the--;

"or" should be --of.;...; line 7'2, after "pulse" insert --tube--. Col.3, line 2 4, L should be L-4--. Col. 6, line "tee" should be --the---;

line 71 (line 13 01? claim 1), "opens" should be --openings--.

Col. 7, line 6 (line 3 of claim 2) "with" should be --within--;

lines 29 and 30 (lines ll and 12 of claim 5), cancel "at least oneopening said tubes and said series of being in said tubes" and insert--said at least one opening and said series of openin '5: being in saidtubes--;

line 39 line i of claim 7), cancel "sections"; Q line 55 line 5 of claim10) "deposits" should be ---deposit--.

Col. 8, line 39 (line 10 of claim 1%) "pulse" should be --pulses--; line58 (line 3 of claim 16), after "spaced" insert --slots,--.

Signed and sealed this 11th day of January 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer ActingCommissioner of Patents J

1. In signalling drift apparatus comprising: an elongated tubular bodyadapted to be installed in a well-drilling string and having apassageway therethrough for the flow of drilling fluid, pulse-producingmeans in said passageway including a movable member exposed to the flowof drilling fluid and held in a first position responsive to said flow,means for effecting movement of said movable member from said firstposition to another position related to the angular disposition of saidbody upon interruption of the flow of drilling fluid, and a stationarymember for effecting a number of pulses in said drilling fluid as saidmovable member returns to said first position upon resumption of saidflow; the improvement wherein one of said members is provided with aseries of opens therethrough and the other of said members is providedwith at least one opening therethrough, said at least one opening beingprogressively cooperative with said series of openings to allow thepassage of drilling fluid through said passageway when said at least oneopening is aligned with one of said series of openings, and to preventthe passage of drilling fluid when said at least one opening is notaligned with one of said series of openings.
 2. Signalling driftapparatus as defined in claim 1, wherein said members respectively arein the form of a pair of tubes, one tube being coaxially disposed withinthe other.
 3. Signalling drift apparatus as defined in claim 2, whereinthe openings of each of said tubes are formed by circumferentiallyextended slots, said tubes having unslotted sections intermediate theends of the slots, said slots being longer than said unslotted sections.4. Signalling drift apparatus as defined in claim 1, wherein the meansfor effecting movement of said movable member from said first positionincludes a spring and gravity responsive stop means for limiting saidmovement of said movable member to an extent related to the angulardisposition of said body.
 5. Signalling drift apparatus as defined inclaim 1, wherein said means for effecting movement of said movablemember from said first position includes a shaft, said movable memberbeing connected to said shaft, a spring acting on said shaft andnormally biasing the same to move said movable member, gravityresponsive stop means for limiting the extent of said movement of saidmovable member from said first position, said movable member including atube extending longitudinally in said passageway and said stationarymember also including a tube extending longitudinally iN said passagewayin coaxial relation with said movable tube, at least one opening saidtubes and said series of being in said tubes.
 6. Signalling driftapparatus as defined in claim 1, wherein said movable member comprises alongitudinally extended tube having said at least one opening therein,said stationary member comprising a tube coaxial with said movable tubeand having said series of openings spaced axially therealong. 7.Signalling drift apparatus as defined in claim 6, wherein said movabletube has a section without openings that extends along said stationarytube and has an axial length greater than the total axial length of theseries of openings sections of said stationary tube for closing theopenings of all of said series of openings of said stationary tube whensaid movable tube is in said first position.
 8. Signalling driftapparatus as defined in claim 1, including means for shielding saidtubes from the deposit of foreign matter thereon.
 9. Signalling driftapparatus as defined in claim 8, wherein said means for shielding alsoprovides nozzle means for increasing the velocity of air flow throughsaid movable member.
 10. Signalling drift apparatus as defined in claim1, wherein said members respectively are in the form of tube members,one tube member being coaxially disposed within the other tube member,and including means for shielding said tubes from the deposite offoreign matter thereon comprising a blowtube extending coaxially intothe inner of said tube members.
 11. Signalling drift apparatus asdefined in claim 1, wherein said members respectively are in the form oftube members, one tube member being coaxially disposed within the othertube member, said series of openings and said at least one opening beingprovided in said tube members and being in the form of circumferentiallyextended axially spaced slots, and including means for shielding saidtubes from the deposit of foreign matter thereon comprising a blowtubeextending coaxially into the inner of said tube members to a pointspaced from the nearest slot.
 12. Signalling drift apparatus as definedin claim 1, wherein said means for effecting movement of said movablemember from said first position includes a shaft, said movable memberbeing connected to said shaft, a spring acting on said shaft andnormally biasing the same to move said movable member, gravityresponsive stop means for limiting the extent of said movement of saidmovable member from said first position, said movable member including atube extending longitudinally in said passageway and said stationarymember also including a tube extending longitudinally in said passagewayin coaxial relation with said movable member, said series of openingsbeing in said tubes, and including means for shielding said tubes fromthe deposit of foreign matter thereon comprising another tube extendingaxially into said tube of said movable member.
 13. Signalling driftapparatus adapted to be disposed in an elongated drill collar sub,comprising: an elongated housing having a body of clean fluid therein, adivider movably disposed in one end of said housing, a shaftreciprocable in said housing and having an end projecting from the otherend of said housing, means for effecting a seal between said shaft andsaid housing, a spring in said housing acting on said shaft for causingsaid shaft to be moved outward with respect to said housing, gravityresponsive stop means in said housing for limiting outward movement ofsaid shaft to an extent related to the disposition of said housingrelative to vertical, pulse tube means carried by said housing, a knobon said end of said shaft, knob tube means on said knob and extendingaxially into said pulse tube means, said pulse tube means and said knobtube means together operatively defining valve means progressivelyopenable and closable in response to movement of said knob tube meansaxially in said pulse tube means, a blowtube, means supporting saidblowtube in coaxial relation To said pulse tube means and said knob tubemeans with the lower end of said blowtube telescopically fitting withinsaid knob tube means.
 14. In signalling drift apparatus comprising: anelongated tubular body adapted to be installed in a well drilling stringand having a passageway therethrough for the flow of drilling fluid,pulse-producing means in said passageway including a movable memberexposed to the flow of drilling fluid and held in a first positionresponsive to said flow, means for effecting movement of said memberfrom said first position to another position related to the angulardisposition of said body upon interruption of the flow of drillingfluid, and a stationary member for effecting a number of pulses in saiddrilling fluid as said movable member returns to said first positionupon resumption of said flow; the improvement wherein said stationarymember comprises an elongated tube in said passageway, and said movablemember comprises an elongated tube coaxial with said stationary tube,one of said tubes having alternately in axially spaced relationtherealong a series of openings connecting said passageway in saidstationary tube with the passageway below said stationary tube, saidmovable tube having at least one opening movable successively past saidseries of openings of said stationary tube.
 15. Signalling driftapparatus as defined in claim 14, wherein said movable tube includes apair of axially spaced openings spaced a distance equal to the spacesbetween adjacent openings of said series of openings of said stationarytube for registry with the adjacent openings of the latter. 16.Signalling drift apparatus as defined in claim 15, wherein said openingsof each of said tubes are formed by circumferentially extended andcircumferentially spaced said slots being longer circumferentially thanthe spacers therebetween.
 17. Signalling drift apparatus adapted to bedisposed in an elongated drill collar sub, comprising: an elongatedhousing having a body of clean fluid therein, a divider movably disposedin one end of said housing, a shaft reciprocable in said housing andhaving an end projecting from the other end of said housing, means foreffecting a seal between said shaft and said housing, a spring in saidhousing acting on said shaft for causing said shaft to be moved outwardwith respect to said housing, gravity responsive stop means in saidhousing for limiting outward movement of said shaft to an extent relatedto the disposition of said housing relative to vertical, pulse tubemeans carried by said other end of said housing and extending axiallytherefrom, a knob on said end of said shaft, knob tube means on saidknob and extending axially into said pulse tube means, said knob tubemeans and said pulse tube means having valve means progressivelyopenable and closable in response to movement of said knob tube meansaxially in said pulse tube means, said valve means includes a series ofaxially spaced openings in one of said tube means, at least one openingin the other of said tube means, and said other tube means having asection without openings for closing all of said series of openings ofsaid one of said tube means upon inward movement of said shaft to itsinnermost position.